Typical graphical user interfaces (GUIs) serially process input signals that are received from input devices such as a mouse or a keyboard. Serial processing of inputs to a multi-user GUI may, however, provide an inappropriate result. For instance, if two users provide inputs to a GUI, the GUI may process the first input that is directed at an active window, without regard for the other input. Accordingly, current GUI implementations may provide inappropriate results when dealing with multiple inputs.